Production of anti-corrosive coatings for metals



uuyqaq l\L-i Lin-nu L/U'iiilllih.

ilth-95 Patented Feb. 2, 1960 This is made into a paste or slurry withwater to which 2,923,643 about 2% of polyvinyl acetate is added. Thesurface to PRODUCTION OF ANTl-CORROSIVE COATINGS FOR METALS RobertHunter Rodwell, London, England, assignor to EH3! and Company (Paints)Limited, London, Eng- No Drawing; Application May 29, 1958 average usewould have a ring and ball softening point fl 733,544 of approximately250 F. but this may vary quired H Claims P y, application Great BritainJune 18, 1957 53 parts solvent such 5 bite a: a suitable coal v 2Claims. (Cl. 117-70) tar solvent 2 parts Portland cement or e'subs'tancewhich sets on i This invention relates to the coating of metalsparticuhydration with water larly iron and steel, with an anti-corrosivecoating, and Exam 3 the object of the invention is to provide a coatingapplip cable to pontoons, ships hulls, metal buildings, struc- 30 partsresidual bitumen, with a ring and ball softening tural steel and allsimilar surfaces which are exposed to point of approximately 200 F.varying atmospheric conditions of temperature and 12 parts naturalasphaltum such as gilsonite (preferably humidity. of American origin)The invention consists in a process of producing an 58 parts solventsuchaswhite spirit anti-corrosive coating on metals such as iron andsteel which comprises applying to the metal surface, one or Example 4more coati g of an aqueous suspqnsion of Portland 9 40 parts residualbitumen, with a ring and ball softening like cement which sets onhydration with water, said oimof approximately 220 suspension containingzinc rom e and p vinyl 9 parts rosin modified phenol-formaldehyde resinesterifate, and if desired, also a gelling agent such as bentonite fledi h l i having a i and b l ft i and a a t i g agent such as a p.allowing the point of 120-130 C. such as that sold under the 9 s orcoatings t y and pp y ps to the dried registered trademark Mitchanol IQE one more bituminous resinous matmgs- 51 parts solvent, such as whitespirit or a suitable coal The polyvinyl acetate may be incorporated inthe msglvent water employed in making the aqueous suspension of Theabove compositions may be prepared as follows. ii g i Spirit is definedas an essentially petroleum Bitumen and white spirit may be mixedtogether in a hydrocarbon fraction of approximately boiling range vesselcapable of being heated to a temperature of 160 140-210 0., known alsoas mineral spirits and a comand prefeliably i remixing condenser Hits);constituent thinner of air drying paints and varfig g ifgggf 2 $22? giggg g g 22: 3: ru es.

- bitumen white spirit mixture is homogeneous.

2% aqueous suspension of a polyvinyl acetate paste, 4Q which isavailable on the market, may be employed and a z g f the following 5111/this improves the adhesion of the dried cement mix to o yams may amp 0ythe metal surface to which it is applied. Example 5 Moreover thepresence of the polyvinyl acetate in the dried coating enables thebituminous or resinous coating 35 Parts drying 011 M linseed lfp 30-40P0156 VISCOSIW subsequently applied to become firmly adhered thereto. 8Such as the Processed 011 knOWn under the 1 The invention also consistsin a dry mix for carrying plastybfwl out the process, comprisingPortland or like cement and 25 Paris $05111 modlfied Phfllollc as 111 EP zinc chromate and if desired, a gelling agent such as P 8 p p h n te(10% by weight disbentonite and a wetting agent such as adehydrate'dsoap. solved Whlte 9 In carrying out the present inventionthe surface to be P qq napthanaie y Weight dissolved in coated is firsttreated to remove any corrosion already 3pm!) present and there is thenapplied to the surface by brush- 38-83 P Solvent, Such as Whlte D ing,spraying, or trowelling, one or more coatings of an aqueoussuspension ofthe cement mix. The cement x222 2 22 m gi gg fi g g ordmary cqaung lsallowed to bcFome dry and Is Heat the oil to 150 C. Add resin anddissolve, increasplied to the cement coating one or more coats of aproing the temperature to approximately C Cool to tective compositionwhich may be bituminous in nature, C Add driers and solvent ashereinafter described or alternatively, aselecte d resin/ It to beunderstood different 8 nthefic or oil varnish may be used, ashereinafter described, either natural "sins and drying oils may beselecfed and the of may be pgmemed if a Mound s is proportions of eachcomponent varied accordingly. g z q' i cement g; g g on One or morecoatings of the bituminous or oil/resin y 997 .1 W .3 5 e a e to etummous composition maybe applied to the cement coated surface, coatmg ai m f allowing each coating to dry before another is applied.

5mm e ceinent composlilonfn 9 0m gt a 65 The final coating may, ifdesired, contain additional ceg i g Fompnse the following m which theparts are ment which may be added just prior to application.

y E I I Also, if desired, a final coating of a composition,

8 bituminous or otherwise, pigmented with metallic paste 96 partsPortland cement or powder-for example aluminum-may be applied to 3 partszinc chromate the surface. Such coatings have been found an ad- .98 partbentonite (preferably by Wyoming origin) .02 part dehydrated potassiumoleate be treated is evenly coated with the slurry.

Suitable bituminous compositions may comprise the following in which theparts are by weight:

Example 2 45 parts residual bitumen. An appropriate grade for vantage inreflecting the suns heat, for example from storage tanks, thus effectingsome reduction in the temperature of the contents when exposed for longperiods to the sun.

It is to be understood that the quantities of the components and thegrades selected may be varied to suit individual requirements.

I claim:

1. In the process of producing an anti-corrosive coating on metals whichcomprises applying to the metal surface at least one coating of anaqueous suspension of a hydratable cement, said suspension containingzinc chromate of the order of 3%, the improvement comprisingincorporating in the suspension polyvinyl acetate of the order of 2% ofthe water employed in the slurry, allowing the coating to dry andapplying to the dried coating at least one coating selected from thegroup consisting of bitumen and synthetic resin in a solvent vehicle.

2. In the process of producing an anti-corrosive coating on metals whichcomprises applying to the metal surface at least one coating of anaqueous suspension of a hydratable cement, said suspension containingzinc chromate of the order of 3%, the improvement comprisingincorporating in the suspension polyvinyl acetate of the order of 2% ofthe water employed in the slurry, a gelling agent and a soap, allowingthe coating to dry and applying to the dried coating at least onecoating selected from the group consisting of bitumen and syntheticresin in a solvent vehicle.

References Cited in the file of this patent UNITED STATES PATENTS2,231,370 Reid Feb. 11, 1941 2,434,302 Wertz Jan. 13, 1948 2,733,995Robinson Feb. 7, 1956 2,760,885 Larsen Aug. 28, 1956 2,835,599 SnyderMay 20, 1958 FOREIGN PATENTS 3,527 Great Britain AD 1899 20,227

Australia Apr. 16, 1935

1. IN THE PROCESS OF PRODUCING AN ANTI-CORROSIVE COATING ON METALS WHICHCOMPRISES APPLYING TO THE METAL SURFACE AT LEAST ONE COATING OF ANAQUEOUS SUSPENSION OF A HYDRATABLE CEMENT, SAID SUSPENSION CONTAININGZINC CHROMATE OF THE ORDER OF 3%, THE IMPROVEMENT COMPRISINGINCORPORATING IN THE SUSPENSION POLYVINYL ACETATE OF THE ORDER OF 2% OFTHE WATER EMPLOYED IN THE SLURRY, ALLOWING THE COATING TO DRY ANDAPPLYING TO THE DRIED COATING AT LEAST ONE COATING SELECTED FROM THEGROUP CONSISTING OF BITUMEN AND SYNTHETIC RESIN IN A SOLVENT VEHICLE.